Disposable elastic thermal uniaxial joint wrap

ABSTRACT

The present invention relates to disposable elastic thermal uniaxial joint wraps having an elastic laminate structure formed from a polymeric mesh and two fabric carrier layers, and one or more heat cells, preferably one or more thermal packs comprising a plurality of individual heat cells, wherein heat is applied to specific areas of the user&#39;s body, preferably for the knee and/or elbow, preferably for pain relief. These wraps provide good conformity to user&#39;s body to deliver consistent, convenient and comfortable heat application.

TECHNICAL FIELD

The present invention relates to disposable elastic thermal uniaxialjoint wraps having an elastic laminate structure formed from a polymericmesh and two fabric carrier layers, and one or more heat cells, suchthat heat is applied to specific areas of the user's body, preferablyfor pain relief. More particularly, the present invention relates todisposable elastic thermal uniaxial joint wraps, preferably for the kneeand/or elbow, having an elastic laminate structure and one or morethermal packs comprising a plurality of individual heat cells providinggood conformity to user's body to deliver consistent, convenient andcomfortable heat application.

BACKGROUND OF THE INVENTION

A common method of treating temporary or chronic pain is by applicationof heat to the afflicted area. Such heat treatments are used as a meansof therapy for conditions which include aches, stiffness in muscles andjoints, nerve pain, rheumatism and the like.

The human knee and elbow are two of the most vulnerable joints of thehuman body to overstress injury. While elastic compression bandages havebeen used to help stabilize knee movement during injury healing, heatingpads, whirlpools, hot towels, and hydrocollators have been commonly usedto apply heat to the knee to relieve the pain of knee injury. These painrelieving and stabilization devices, however, typically provide eitherone function or the other, but not both.

In general, the beneficial therapeutic effects from the administrationof heat diminish after the heat source is removed. Therefore, dependingon the temperature, it is desirable to provide a sustained heat sourceto the afflicted area for as long as possible to achieve the desiredtherapeutic benefits. Many of the current heating devices which requirethe thermal source to be replenished, such as the devices mentionedabove or those employing reusable thermal packs containing water and/ormicrowaveable gels, are inconvenient to use on a regular and extendedbasis because the heat energy may not be immediately available whenneeded or released in a controllable manner.

Disposable heat packs based on iron oxidation, such as those describedin U.S. Pat. Nos. 4,366,804, 4,649,895, 5,046,479 and Re.32,026, havebeen developed, however, such devices have proven not totallysatisfactory. Many of these devices are bulky, cannot maintain aconsistent and controlled temperature, and/or have unsatisfactoryphysical dimensions which hinder their effectiveness, and hence, deliverinconsistent, inconvenient and/or uncomfortable heat application to thebody.

Proper positioning of the thermal energy also may not be maintainableduring knee or elbow flexure with current heating devices. Elasticlaminate structures have previously been used in a variety of productsincluding elastic absorbent structures such as sweat bands, bandages,diapers, and incontinence devices. Several methods for producing theselaminate structures, such as those disclosed in U.S. Pat. Nos.4,522,863, 4,606,964, and 4,977,011, also currently exist. However,while these elastic laminate structures may be suitable for the purposesfor which they were intended, they have strands which protrude on cutsides of the structure such that they can be a source of irritation whenworn next to the body. Further, if an elastic laminate structure havinga large modulus value (i. e., the ratio of stress to strain) is desired,elastic strands having a large cross-sectional area are generallyrequired. Large strands of this type, however, can produce a rough or"nubby" feeling when placed in contact with the body.

The present inventors have developed disposable elastic thermal uniaxialjoint wraps which maintain proper positioning during use on a user'sknee or elbow while providing both compression and thermal energy in acontrolled and sustainable manner. These wraps comprise one or morethermal bonded elastic laminate structures, which preferably comprisetwo carrier layers and an elastic member integrally thermal bondedtherebetween, and one or more heat cells, preferably one or more thermalpacks, wherein each thermal pack comprises a plurality of individualheat cells, which typically comprise an exothermic composition,preferably comprising a specific iron oxidation chemistry and specificphysical dimensions and fill characteristics, spaced apart and fixedlyattached across the thermal pack. The thermal bonded elastic laminatestructures, when incorporated into the knee and/or elbow wraps of thepresent invention, substantially reduce delamination of the compositestructure of the wraps during use, substantially reduce the rough and"nubby" feeling and irritation caused by strands protruding from cutedges, and provide the knee and/or elbow wraps with excellent conformityto the user's knee and/or elbow for uniform heat coverage and enhancedcomfort.

It is therefore an object of the present invention to provide disposableelastic uniaxial joint wraps having excellent conformity to the user'sknee and/or elbow for uniform heat coverage and enhanced comfort, whichcomprise one or more thermal bonded elastic laminate structures and oneor more heat cells, which provide a controlled and sustained temperatureand which reach their operating temperature range relatively quickly.

It is a further object of the present invention to provide disposableelastic uniaxial joint wraps, which comprise one or more thermal bondedelastic laminate structures, which comprise two carrier layers and anelastic member integrally bonded therebetween and one or more thermalpacks comprising a plurality of individual heat cells. Such elasticlaminate structures substantially reduce delamination of the compositestructure of the wraps, substantially reduce the rough or "nubby"feeling and irritation caused by strands protruding from cut edges, andprovide consistent, convenient, and comfortable heat application whiledeterring easy access to the heat cell contents.

It is a still further object of the present invention to providedisposable elastic uniaxial joint wraps, preferably for the knee and/orelbow, which comprise one or more thermal bonded elastic laminatestructures, which preferably comprise two carrier layers and an elasticmember integrally bonded therebetween, and one or more thermal packshaving a unified structure of at least one continuous layer of semirigidmaterial, which has different stiffness characteristics over a range oftemperatures, and a plurality of individual heat cells, spaced apart andfixedly attached across the unified structure of the thermal packproviding good overall drapability while maintaining sufficient rigidityto maintain structural support of the heat cells and to preventunacceptable stretching of the continuous layer or layers duringprocessing or use.

These objectives and additional objectives will become readily apparentfrom the detailed description which follows.

SUMMARY OF THE INVENTION

The disposable elastic thermal uniaxial joint wraps of the presentinvention, comprise a piece of flexible material having an outersurface, a body-facing surface, a first end, a second end, a bodyportion, a first strap portion, a second strap portion, wherein at leastone of body portion, first strap portion, and second strap portioncomprise an elastic portion stretchable along a longitudinal axis of thepiece of flexible material, and one or more heat cells comprising anexothermic composition, which preferably substantially fills theavailable cell volume within the cell.

The elastic portion of the flexible material comprises a laminatestructure having a first carrier layer, a second carrier layer, and amesh disposed between the first and second carrier layers. The mesh ispreferably elastic in at least one direction and comprises a pluralityof first strands intersecting a plurality of second strands, whereinfirst and second strands have softening temperatures, at an appliedpressure, such that at least 10% of first strands are integrally bondedto first and second carrier layers by application of a bonding pressureat the softening temperature of the first strands.

The piece of flexible material has a length great enough to encircle auser's knee and/or elbow such that the first and second ends overlapwhen the flexible material is in a relaxed or stretched state. The firstand second ends comprise a reclosable fastening means, preferably a hookand loop fastening system, for attaching the first end to said piece offlexible material in order to hold said piece of flexible materialaround the user's knee or elbow. More preferably, the fastening meanscomprises a two-part fastening means which additionally comprises aplurality of hook members which engage loop fibers of a landing zoneattached to, or part of, the piece of flexible material in order toadjust the wrap to a variety of user sizes and to attain a comfortablelevel of elastic tension.

The piece of flexible material preferably comprises an aperture thereinintended to be aligned with the user's patella (knee) or olecranon(elbow) to establish a convenient locating point for wrapping theuniaxial joint wrap around the user's knee or elbow. The piece offlexible material preferably comprises a slit extending substantiallylongitudinally from the aperture for enabling the piece of flexiblematerial to stretch transverse to the longitudinal axis at the aperturein order to accommodate bending of the user's knee or elbow.

The elastic thermal uniaxial joint wraps preferably comprise one or morethermal packs, preferably embedded in the piece of flexible material, toapply thermal energy to the user's knee or elbow. The thermal pack orpacks comprise a unified, structure comprising at least one continuouslayer of a coextruded film, preferably comprising a first side ofpolypropylene and a second side comprising a low melt temperaturepolymer, which has different stiffness characteristics over a range oftemperatures. The thermal pack or packs further comprise a plurality ofindividual heat cells which provide a controlled and sustainedtemperature and which reach their operating temperature range quickly.The heat cells are spaced apart and fixedly attached within each thermalpack. Each thermal pack provides good drapability while maintainingsufficient rigidity to maintain structural support of the heat cells andto prevent unacceptable stretching of the continuous layer or layersduring processing or use, providing consistent, convenient andcomfortable heat application. Preferably, the heat cells comprise amixture of powdered iron, powdered carbon, water, and metal salt, whichwhen exposed to oxygen, provides heat for several hours.

The present invention further comprises methods for making disposableelastic thermal uniaxial joint wraps, wherein the elastic laminatestructure is formed prior to assembly of the flexible material andcomprises the steps of:

a) providing a first carrier layer;

b) providing a second carrier layer;

c) providing a mesh disposed between the first and second carrierlayers, having a plurality of first strands intersecting a plurality ofsecond strands, the first and second strands having softeningtemperatures at an applied pressure, wherein the softening temperatureof the second strands, at the applied pressure, is greater than thesoftening temperature of the first strands at the applied pressure;

d) heating the mesh to the softening temperature of first strands andless than the softening temperature of the second strands;

e) applying a bonding pressure to the first strands; and

f) integrally bonding from about 10% to about 100% of the first strandsto the first and second carrier layers.

All percentages and ratios used herein are by weight, and allmeasurements made at 25° C., unless otherwise specified.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which particularly pointout and distinctly claim the present invention, it is believed that thepresent invention will be better understood from the followingdescription of preferred embodiments, taken in conjunction with theaccompanying drawings, in which like reference numerals identifyidentical elements and wherein:

FIG. 1 is a top plan view of a preferred embodiment of the presentinvention, showing the preferred pattern of heat cells and/or thermalpack(s);

FIG. 2 is a sectioned side elevation view of FIG. 1, disclosing thelaminate structure of the present invention;

FIG. 3 is an exploded view of a mesh and first and second carrier layerprior to being formed into a laminate structure, made in accordance withthe present invention;

FIG. 4 is a partial perspective view of a laminate structure made inaccordance with the present invention, wherein a portion of the carrierlayers have been removed to show the integrally bonded first strands;

FIG. 4A is an enlarged partial perspective view of an integrally bondedfirst strand of the laminate structure of FIG. 4;

FIG. 5 is a schematic representation of a preferred process according tothe present invention for forming the laminate structure of FIG. 4; and

FIG. 6 is a schematic representation of a plate process according to thepresent invention for forming the laminate structure of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

The disposable elastic thermal uniaxial joint wraps of the presentinvention comprise at least one elastic portion of flexible materialhaving at least one elastic laminate structure, wherein the laminatestructure comprises at least one elastic member integrally thermalbonded between a first carrier layer and second carrier layer, and atleast one heat cell. Preferably the disposable elastic thermal knee wrapof the present invention comprises at least one elastic laminatestructure and one or more thermal packs having at least one continuouslayer of a material, which exhibits specific thermophysical propertiesand a plurality of individual heat cells spaced apart and fixedlyattached across the thermal pack, providing good overall drapabilitywhile maintaining sufficient rigidity to maintain structural support ofthe heat cells and to prevent unacceptable stretching of the continuouslayer or layers during processing or use. The disposable elastic thermaluniaxial joint wrap of the present invention, provides consistent,convenient, and comfortable heat application, and an excellentconformity to the user's knee or elbow, while retaining sufficientrigidity to deter easy access to the heat cell contents.

The term "disposable", as used herein, means that, while the elasticthermal wraps of the present invention may be stored in a resealable,substantially air impermeable container and reapplied to the user's bodyas often as required for the relief of pain, they are intended to bethrown away, i. e., deposited in a suitable trash receptacle, after theheat source, i. e., the heat cell(s) or thermal pack(s), has been fullyexpended.

The term "heat cells", as used herein, means a unified structure,comprising an exothermic composition, preferably a specific ironoxidation chemistry, enclosed within two layers, wherein at least onelayer may be oxygen permeable, capable of providing long lasting heatgeneration with improved temperature control, and having specificphysical dimensions and fill characteristics. These heat cells can beused as individual heating units, or in a thermal pack comprising aplurality of individual heat cells which can also be easily incorporatedinto disposable body wraps, pads, and the like. Body wraps incorporatingheat cells or thermal packs adapt to a wide variety of body contours,thus providing consistent, convenient, and comfortable heat application.

The term "direct compaction", as used herein, means a dry powder mixtureis blended, compressed, and formed into pellets, tablets, or slugswithout the use of typical wet binders/solutions to adhere theparticulate(s) together. Alternatively, the dry powder mixture isblended and roll compacted or slugged, followed by milling andscreening, creating directly compacted granules. Direct compaction mayalso be known as dry compaction.

The term "fill volume", as used herein, means the volume of theparticulate composition or the compacted, water-swelled, heating elementin the filled heat cell.

The term "void volume", as used herein, means the volume of the cellleft unfilled by the particulate composition or the compacted heatingelement in a finished heat cell.

The term "cell volume", as used herein, means the fill volume plus thevoid volume of the heat cell.

The term "continuous layer or layers", as used herein, means one or morelayers of a material which may be uninterrupted or partially, but notcompletely, interrupted by another material, holes, perforations, andthe like, across its length and/or width.

The term "semirigid material", as used herein, means a material which isrigid to some degree or in some parts and exhibits a toughness tomaintain structural support of the heat cells in an unsupported format,and/or to prevent unacceptable stretching of structures of the materialduring processing or use and/or to deter easy access to the heatingelement contents while still maintaining good overall drapecharacteristics when heated.

Referring now to the drawings, and more particularly to FIGS. 1 and 2,there is shown a preferred embodiment of the present invention, whichprovides a disposable elastic thermal uniaxial joint wrap, and isgenerally indicated as 10. Wrap 10 comprises a piece of flexiblematerial 12 having a longitudinal axis 18.

Flexible material 12 comprises a first end 14 and a second end 16, abody portion 81, and preferably a first strap portion 80 and secondstrap portion 82, wherein at least one of body portion 81, first strapportion 80, and second strap portion 82 comprise elastic portion 20capable of being stretched along longitudinal axis 18. Flexible material12 has a length, when in a relaxed or stretched state, as measured in adirection parallel to longitudinal axis 18 from first end 14 to secondend 16, which is great enough to encircle a user's knee or elbow suchthat first end 14 overlaps second end 16. Flexible material 12 has abody-facing material 62, comprising body-facing surface 28, and an outersurface material 64, comprising outer surface 30, extending from firstend 14 to second end 16.

As used herein, "elastic" refers to that property of a material wherebythe material, when subjected to a tensile force, will stretch or expandin the direction of the force and will essentially return to itsoriginal untensioned dimension upon removal of the force. Morespecifically, the term "elastic" is intended to mean a directionalproperty wherein an element or structure has a recovery to within about10% of its original length Lo after being subjected to a percent strainε_(%) of greater than 50%. As used herein, percent strain ε_(%) isdefined as:

    ε.sub.% = (L.sub.f -L.sub.o)/L.sub.o !*100

Where

L_(f) =Elongated Length

L_(o) =Original Length

For consistency and comparison, the recovery of an element or structureis preferably measured 30 seconds after release from its elongatedlength L_(f). All other elements or structures will be consideredinelastic if the element or structure does not recover to within about10% of its original length L_(o) within 30 seconds after being releasedfrom a percent strain ε_(%) of 50%. Inelastic elements or structureswould also include elements or structures which fracture and/orpermanently/plastically deform when subjected to a percent strain ε_(%)of 50%.

Referring now to FIGS. 1-4, elastic portion 20 of flexible material 12comprises a first elastic member 36. First elastic member 36 ispreferably thermally bonded to first carrier layer 37 and second carrierlayer 38 prior to assembly of flexible material 12 to form first thermalbonded elastic laminate 66. First thermal bonded elastic laminate 66 isthen fixedly attached to body-facing material 62, by hot melt adhesivelayer 60 to form body-facing laminate 92.

Preferably, elastic portion 20 of flexible material 12 further comprisesa second elastic member 39. Second elastic member 39 is preferablythermally bonded to third carrier layer 40 and fourth carrier layer 41prior to assembly of flexible material 12 to form second thermal bondedelastic laminate 67. Second thermal bonded elastic laminate 67 is thenfixedly attached to outer surface material 64, by hot melt adhesivelayer 60 to form outer surface laminate 93. Body-facing laminate 92 isthen fixedly attached to outer surface laminate 93 with one or moreindividual heat cells 75, preferably one or more thermal packs 22,interposed therebetween, by hot melt adhesive layer 60, to form wrap 10.

Referring now to FIGS. 3 and 4 elastic members 36 and 39 comprise aplurality of first strands 24 which intersect or cross (with or withoutbonding to) a plurality of second strands 26 at nodes 31 at apredetermined angle α, thereby forming a net-like open structure havinga plurality of apertures 33. Each aperture 33 is defined by at least twoadjacent first strands (i. e., 42 and 43) and at least two adjacentsecond strands (i. e., 44 and 45) such that apertures 33 aresubstantially rectangular (preferably square) in shape. Other apertureconfigurations, such as parallelograms or circular arc segments, canalso be provided. Such configurations could be useful for providingnon-linear elastic structural directions. It is preferred that firststrands 24 are substantially straight and substantially parallel to oneanother, and, more preferably, that second strands 26 are alsosubstantially straight and substantially parallel to one another. Mostpreferably, first strands 24 intersect second strands 26 at nodes 31 ata predetermined angle α of about 90 degrees. Each node 31 is an overlaidnode, wherein first strands 24 and second strands 26 are preferablyjoined or bonded (although it is contemplated that joining or bondingmay not be required) at the point of intersection with the strands stillindividually distinguishable at the node. However, it is believed thatother node configurations such as merged or a combination of merged andoverlaid would be equally suitable.

Although it is preferred that first and second strands 24 and 26 besubstantially straight, parallel, and intersect at an angle α of about90 degrees, it is noted that first and second strands 24 and 26 canintersect at other angles α, and that first strands 24 and/or secondstrands 26 can be aligned in circular, elliptical or otherwise nonlinearpatterns relative to one another. Although for ease of manufacture it iscontemplated that first strands 24 and second strands 26 have asubstantially circular cross-sectional shape prior to incorporation intolaminate structures 66 and/or 67, first and second strands 24 and 26 canalso have other cross-sectional shapes such as elliptical, square,triangular, or combinations thereof.

The material of first strands 24 is chosen so that first strands 24 canmaintain second strands 26 in relative alignment prior to forminglaminate structures 66 and/or 67. It is also desirable that thematerials of first and second strands 24 and 26 be capable of beingdeformed (or initially formed) into predetermined shapes uponapplication of a predetermined pressure or a pressure in combinationwith a heat flux, as described in more detail hereafter. These deformedshapes (i. e., elliptical second strands, substantially flat firststrands and the like) provide laminate structures 66 and 67 which can becomfortably worn about the body without irritation or other discomfort.It is further desirable that the material chosen for first strands 24provide an adhesive-like property for joining a portion of second strandouter surface 49 of deformed second strands 27 to a portion of firstcarrier layer inner surface 50 and second carrier layer inner surface52.

The material of first strands 24 should also be capable of integrallybonding with carrier layers 37, 38, 40 and/or 41 as part of forminglaminate structure 66 and/or 67. As described in more detail hereafter,first strands 24 can be integrally bonded to carrier layers 37, 38, 40and/or 41 by application of a pressure or a pressure in combination witha heat flux. As used herein, the phrase "integrally bonded" and itsderivatives is intended to mean that a portion of a strand outer surface(i. e., first strand outer surface 47) of an integrally bonded strand(i. e., integrally bonded first strands 25) has penetrated into andbonded with carrier layer 37,38, 40, and/or 41. The portion of thestrand outer surface of an integrally bonded strand which penetratescarrier layer 37, 38, 40, and/or 41 can bond mechanically (i. e., as byencapsulating, encircling or otherwise engulfing) and/or chemically (i.e., polymerizing, fusing or otherwise chemically reacting) with fibers51 of carrier layers 37, 38, 40, and/or 41, as shown in FIG. 4A. Withregard to penetration, integrally bonded means that a portion of thestrand outer surface has penetrated at least about 10%, preferably atleast about 25%, more preferably at least about 50%, even morepreferably at least about 75%, most preferably about 100% of carrierlayer structural thickness T of carrier layer 37, 38, 40, and/or 41 inlaminate structure 66 and/or 67. Further, because integrally bondedstrands enhance the comfort of laminate structures 66 and/or 67 whenworn about the body, at least about 10%, preferably at least about 50%,more preferably at least about 90%, most preferably about 100%, of firststrands 24 are integrally bonded to carrier layers 37, 38, 40, and/or 41of laminate structures 66 and/or 67.

The above described benefits can be achieved by selecting a first strandmaterial having a softening temperature which is lower than thesoftening temperature of second strands 26 relative to the processingpressures used to form laminate structures 66 and/or 67. As used herein,the phrase "softening temperature" is intended to mean the minimumtemperature at which a material begins to flow under an applied pressureto facilitate integral bonding of the material to a carrier layer orlayers. Typically, heat is applied to a material to achieve a softeningtemperature. This generally results in a decrease in the viscosity ofthe material which may or may not involve a "melting" of the material,the melting being associated with a latent heat of fusion. Thermoplasticmaterials tend to exhibit a lowering in viscosity as a result of anincrease in temperature allowing them to flow when subjected to anapplied pressure. It will be understood that as the applied pressureincreases, the softening temperature of a material decreases andtherefore a given material can have a plurality of softeningtemperatures because the temperature will vary with the appliedpressure. For ease of manufacturing and processing, and when utilizinggenerally polymeric materials for strands 24 and 26, it is preferredthat the softening temperature of first strands 24 be lower, at leastabout 10° C. lower, more preferably at least about 20° C. lower, thanthe softening temperature of second strands 26 when both materials aresubjected to the same applied pressure (e.g., the processing pressure).As used herein, the phrase "bonding pressure", is intended to mean thepressure which facilitates the integral bonding of first strands 24 tocarrier layers 37 and 38, without integrally bonding second strands 26to carrier layers 37 and 38, when both strands are at the softeningtemperature of first strands 24 but below the softening temperature ofsecond strands 26. In addition to the selection of first and secondstrand materials for softening temperature point, second strands 26 arepreferably formed from a material which renders second strands 26appropriately elastic such that laminate structures 66 and/or 67 providea structural direction, along the direction of second strands 26, whichis also appropriately elastic as desired.

Polymers such as polyolefins, polyamides, polyesters, and rubbers (i.e., styrene butadiene rubber, polybutadiene rubber, polychloroprenerubber, nitrile rubber and the like) have been found to be suitable, butnot limited to, materials for forming the first and second strands ofelastic member 36 and/or 39. Other materials or compounds (i. e.,adhesive first strands) having different relative softening temperaturesor elasticity can be substituted so long as the material provides thepreviously described benefits. Additionally, adjunct materials can beadded to the base materials comprising first and second strands (i. e.,mixtures of pigments, dyes, brighteners, heavy waxes and the like) toprovide other desirable visual, structural or functionalcharacteristics.

Elastic members 36 and/or 39 may be formed from one of a variety ofprocesses known in the art. A particularly suitable material for use asfirst and/or second elastic member 36 and/or 39 is an elastic scrimavailable as T50018 from Conwed Plastics, Minneapolis, Minn.

Alternatively, first and second elastic members 36 and 39 may each beselected from natural or synthetic rubber, or any number of polymericmaterials which are capable of elongation and recovery. Suitablematerials include, but are not limited to, styrene block copolymers,rubber, Lycra™, Krayton™, polyethylene including metallocene catalystPE, foams including polyurethane and polyesters, and the like. First andsecond elastic members 36 and 39 may be in the form of films, strands,scrims, ribbons, tapes, structural elastic-like film, and the like.

For ease of manufacture and cost efficiency, carrier layers 37, 38, 40,and/or 41 are preferably formed from, but not limited to, a non-wovenfabric having fibers formed, for example, from polyethylene,polypropylene, polyethylene terepthalate, nylon, rayon, cotton or wool.These fibers can be joined together by adhesives, thermal bonding,needling/felting, or other methods known in the art to form carrierlayers 37, 38, 40 and/or 41. Although it is preferred that carrierlayers 37, 38, 40, and/or 41 are formed from a non-woven fabric, otherfabrics such as wovens and knits, would be suitable.

The softening temperature of carrier layers 37, 38, 40, and/or 41 (atthe subject processing pressures) should be greater than any of theprocessing temperatures applied to elastic member 36 and/or 39 informing laminate structures 66 and/or 67. In addition, carrier layers37, 38, 40, and/or 41 of the present invention preferably have a modulusof less than about 100 gm force per cm at a unit strain ε.sub.μ of atleast about 1 (i. e., L_(f) =2×L_(o)) in a direction along secondstrands 26 when it is formed into laminate structure 66 and/or 67. Asused herein, the term "modulus" is intended to mean the ratio of anapplied stress σ to the resulting unit strain ε.sub.μ, wherein stress σand strain ε.sub.μ are:

    σ=F.sub.a /W

    ε.sub.μ =(L.sub.f -L.sub.o)/L.sub.o

Where

F_(a) =Applied force

W=Orthogonal dimension of the element or structure subjected too theapplied force F_(a) (typically the structure width)

L_(f) =Elongated length

L_(o) =Original length

For example, a 20 gram force applied orthogonally across a 5 cm widefabric would have a stress σ of 4 grams force per cm. Further, if theoriginal length L_(o) in the same direction as the applied force F_(a)were 4 cm and the resulting elongated length L_(f) were 12 cm, theresulting unit strain ε.sub.μ would be 2 and the modulus would be 2grams force per cm.

It is believed that a carrier layer having a modulus of less than about100 grams force per cm in a subject fabric direction will, when thesubject fabric direction is juxtaposed co-directional with elasticsecond strands 26 in laminate structures 66 and/or 67, provide alaminate structure 66 and/or 67 with a modulus along the direction ofsecond strands 26 that is largely a function of the material properties,size, and arrangement of second strands 26. In other words, the modulusof carrier layers 37, 38, 40, and/or 41 will be low enough that themodulus of the second strands 26 will largely determine the modulus oflaminate structures 66 and/or 67 in the subject direction. Thisconfiguration is especially useful if it is desired that laminatestructure 66 and/or 67 provide an elastic structural direction along thedirection of deformed laminate second strands 27.

If carrier layers 37, 38, 40 and/or 41 do not inherently provide thedesired modulus, carrier layers 37, 38, 40 and/or 41 can be subjected toan activation process before or after forming laminate structures 66and/or 67. As taught for instance in U.S. Pat. No. 4,834,741, issued toSabee on May 30, 1989, incorporated in its entirety herein by reference,subjecting carrier layers 37, 38, 40 and/or 41 to an activation process(either separately or as part of laminate structures 66 and/or 67) willplastically deform carrier layers 37, 38, 40 and/or 41 such that it willprovide the desired modulus. In an activation process, such as thattaught by Sabee, carrier layer 37, 38, 40 and/or 41 (or laminatestructure 66 and/or 67 incorporating same) is passed between corrugatedrolls to impart extensibility thereto by laterally stretching carrierlayers 37, 38, 40 and/or 41 in the cross-machine direction. Carrierlayers 37, 38, 40 and/or 41 are incrementally stretched and drawn toimpart a permanent elongation and fabric fiber orientation in thecross-machine direction. This process can be used to stretch carrierlayers 37, 38, 40 and/or 41 before or after joinder of laminatestructures 66 and/or 67. This preferably provides a laminate structurewhich can be extended in an elastic structural direction with minimalforce as carrier layers 37, 38, 40 and/or 41 (and any additional layers)have initially been "activated" or separated in this direction, therebyproviding a low modulus in the subject direction such that the laminatestructure modulus is primarily a function of laminate second strands 27.

Laminate structures 66 and/or 67 are preferably formed by juxtaposingcarrier layers 37, 38, 40 and/or 41 and elastic members 36 and/or 39 andapplying a predetermined pressure or a predetermined pressure and heatflux, depending upon the selected materials for carrier layers 37, 38,40 and/or 41 and elastic members 36 and/or 39, so that first strands 24are integrally bonded to carrier layers 37, 38, 40 and/or 41. Inaddition to integrally bonding first strands 24 to carrier layers 37,38, 49 and/or 41, it is desirable that the above described processdeform first strands 24 so that the shape of integrally bonded firststrand outer surface 47 is substantially flat. The phrase "substantiallyflat" and its derivatives, as used herein, means that integrally bondedfirst strands 25 have a major dimension M (i. e., the largest dimensionparallel to the major axis of the strand cross section as shown in FIG.4) at least about 2 times the length of a minor dimension N (i. e., thesmallest dimension parallel to the minor axis of the strand crosssection as shown in FIG. 4) Thus, it should be clear that an integrallybonded first strand 25 can have irregularities in outer surface 47 (i.e., peaks and valleys and the like, as shown in FIG. 4A) and still bewithin the intended meaning of substantially flat. More preferably, itis desirable that a portion of outer surface 47 of integrally bondedfirst strands 25 is also substantially coplanar with carrier layer innersurfaces 50 and 52 such that minor dimension N is about equal to or lessthan structural thickness T of carrier layers 37, 38, 40 and/or 41 andsubstantially all of minor dimension N is located within structuralthickness T, as generally shown in FIG. 4. It is further contemplatedthat variations in the substantially flat and coplanar shapes ofintegrally bonded first strands 25 can occur along the length of firststrands 25 without deviating from the scope of these definitions. Inother words, due to processing variations, it is noted that portions ofintegrally bonded first strands 25 can be substantially flat and/orcoplanar while other portions along the same strand may not. Theseconfigurations are still considered to be within the definitions ofsubstantially flat and coplanar as set forth above.

The above described shapes of integrally bonded first strands 25advantageously provide laminate structures 66 and/or 67, wherein strands25 do not protrude in a manner which would cause irritation or otherdiscomfort when laminate structures 66 and/or 67 are cut (therebyexposing the ends of integrally bonded first strands 25) and worn aboutthe body. As such, at least about 25%, preferably at least about 50%,more preferably at least about 75%, and most preferably about 100% ofintegrally bonded first strands 25 are substantially flat and coplanar.

In contrast to the substantially flat and coplanar shape of integrallybonded first strands 25 of laminate structures 66 and/or 67, laminatesecond strands 27 are preferably only joined (as opposed to integrallybonded) to carrier layer inner surfaces 50 and 52, as shown in FIG. 4,by application of the above described pressure and heat flux. It iscontemplated, however, that second strands 26 can also be integrallybonded to carrier layers 37, 38, 40 and/or 41 if so desired. Theintegral bonding of first strands 24 to carrier layers 37, 38, 40 and/or41 can also be performed such that first strands 24 act as an adhesiveto intermittently join second strands 26 to carrier layer inner surfaces50 and 52 at nodes 31. Alternatively, second strands 26 can comprise aself-adhering material which aids in joining a portion of second strandouter surfaces 49 to carrier layer inner surfaces 50 and 52.

As seen in FIG. 5, laminate structures 66 and/or 67 are preferablymanufactured by a process comprising a substantially non-resilient firstsurface 148 (i. e., formed from steel or the like), a substantiallynon-resilient second surface 150, and a substantially resilient thirdsurface 152 (i. e., formed from a silicone or other deformable rubber),wherein these surfaces are provided in the form of rollers. Firstsurface 148 is spaced adjacent second surface 150 such that gap 156 isformed therebetween, while second surface 150 and third surface 152 arepositioned in surface contact to one another thereby forminginterference nip 154. Gap 156 is preferably sized such that firststrands 24 and second strands 26 pass easily therethrough.Alternatively, gap 156 may be sized such that second strands 26 aredeformed by passing therethrough.

First carrier layer 37 is juxtaposed adjacent to first elastic member 36which is juxtaposed adjacent to second carrier layer 38 such that whenfed around first surface 148, as seen in FIG. 5, first elastic member 36is disposed between first carrier layer 37 and second carrier layer 38.Preferably, first strands 24 of first elastic member 36 are juxtaposedadjacent inner surface 50 of first carrier layer 37 and second strands26 are juxtaposed adjacent inner surface 52 of second carrier layer 38.First carrier layer 37 is preferably oriented adjacent first surface148. First surface 148 is heated to a temperature T₁, which, incombination with the feed rate of juxtaposed first carrier layer 37,first elastic member 36, and second carrier layer 38 over first surface148, raises the temperature of first strands 24 to, or above, theirsoftening temperature. Because of the low applied pressure P_(d) at gap156, first strands 24 and second strands 26 undergo little if anydeformation thereat.

After juxtaposed first carrier layer 37, first elastic member 36, andsecond carrier layer 38 pass through gap 156, second carrier layer 38 ispreferably oriented adjacent second surface 150 and disposed betweensecond surface 150 and first elastic member 36 and first carrier layer37. Second surface 150 is preferably heated to a temperature T₂, whichin combination with the feed rate of juxtaposed first carrier layer 37,first elastic member 36, and second carrier layer 38 over second surface150, raises the temperature of second strands 26 to their softeningtemperature. Juxtaposed first carrier layer 37, first elastic member 36,and second carrier layer 38 then pass through interference nip 154,wherein first strands 24 are integrally bonded to first carrier layer 37and second carrier layer 38 by the application of first strand bondingpressure P_(b) from second and third surfaces 150 and 152 at nip 154.Resilient third surface 152 provides bonding pressure P_(b) which isuniformly applied to first strands 24 between second strands 26 due tothe conforming nature of resilient third surface 152. More preferably,the application of pressure P_(b) from third surface 152 and heat fluxfrom second surface 150 at temperature T₂ is sufficient to deform firststrands 24 into substantially flat shaped and integrally bonded firststrands 25. Most preferably, the application of pressure and heat fluxis sufficient to deform first strands 24 into integrally bonded firststrands 25 which are substantially coplanar with inner surface 50 offirst carrier layer 37 and second carrier layer 38.

In contrast, at least about 25%, preferably at least about 50%, morepreferably at least about 75%, most preferably about 100%, of secondstrands 26 are deformed into a substantially elliptical shape at nip 154because pressure P_(b) is fully applied to second strands 26 by secondsurface 150. The elliptical cross-sectional shape of second strands 27is desirable if the undeformed cross section of the second strands 26would otherwise produce a "nubby" or rough feel when laminate structures66 and/or 67 are worn about the body. Preferably, the post-nipstructural thickness I of laminate structures 66 and/or 67 is about 50%of the pre-nip structural thickness S of juxtaposed first carrier layer37, first elastic member 36, and second carrier layer 38.

The feed rate of juxtaposed first carrier layer 37, first elastic member36, and second carrier layer 38 through first, second, and thirdsurfaces 148, 150, and 152 can be adjusted so that first and secondstrands 24 and 26 have a sufficient residence time adjacent heated firstand second surfaces 148 and 150 so that these strands can be softenedand deformed as described herein.

Based upon the foregoing described nip process, it has been found thatthe following will form satisfactory laminate structures 66 and/or 67having an elastic structural direction along the direction of laminatesecond strands 27: first, second, third, and fourth carrier layers 37,38, 40 and 41 preferably comprise a carded nonwoven formed fromthermally bonded polypropylene and having a 32 gram per m² basis weight,a fiber size of about 2.2 denier per filament, a caliper of betweenabout 0.01 cm to about 0.03 cm, a modulus of about 100 grams force percm at a unit strain ε.sub.μ of 1 (such a fabric being marketed byFibertech, Landisville, N.J., as Phobic Q-1); and first and secondelastic members 36 and 39 comprise a mesh wherein first strands 24 areformed from polyethylene and second strands 26 are formed from a styreneor butadiene block copolymer (such a mesh being manufactured by Conwed,Minneapolis, Minn. and marketed as T50018). Specifically, the juxtaposedPhobic Q-1 fabric, T50018 mesh, and Phobic Q-1 fabric, having apre-formed structural thickness S of from about 0.09 cm to about 0.13cm, preferably from about 0.10 cm to about 0.12 cm, more preferablyabout 0.11 cm, are fed at a rate of from about 6 to about 14, morepreferably from about 7 to about 12, most preferably from about 8 toabout 10 meters per minute, over first surface 148 which is heated to atemperature T₁ of from about 71° C. to about 141° C., preferably fromabout 130° C. to about 141° C., more preferably from about 137° C. toabout 139° C. In a preferred arrangement, gap 156 is preferably greaterthan or about 0.13 cm. Preferably, second surface 150 is heated to atemperature T₂ of from about 71° C. to about 141° C., preferably fromabout 130° C. to about 141° C., more preferably from about 137° C. toabout 139° C., as the juxtaposed fabrics and mesh pass over secondsurface 150 and through inference nip 154. Pressure P_(b) at nip 154 ispreferably from about 55 to about 85 kilograms per centimeter, morepreferably from about 70 to about 75 kilograms per centimeter. After thejuxtaposed fabrics and mesh emerge from nip 154, the resulting thermalbonded elastic laminates 66 and/or 67 have a thickness I of from about0.05 cm to about 0.09 cm, preferably from about 0.06 cm to about 0.08cm, more preferably about 0.07 cm.

In addition to forming a laminate structure of the present invention viathe is above described nip process, such laminate structures can also beformed by a process providing a first plate 150 and a second plate 160,such as shown in FIG. 6. In contrast to the process discussedpreviously, first plate surface 149 preferably is substantiallynon-resilient, while second plate surface 151 is substantiallyresilient. First plate surface 149 is preferably heated to temperatureT₁. A bonding pressure P_(f) is applied to the juxtaposed fabrics andmesh by moving first plate surface 149 toward second plate surface 151appropriately. Because temperature T₁ heats first strands 24 to theirsoftening temperature for the applied bonding pressure P_(f),application of the bonding pressure P_(f) integrally bonds first strands24 to carrier layers 37 and 38. More preferably, application of thebonding pressure P_(f) also deforms first strands 24 into asubstantially flat shape which is also coplanar with carrier layer innersurfaces 50 and 52. Most preferably, application of bonding pressureP_(f) also deforms second strands 26 into a substantially ellipticalshape.

Using the Phobic Q-1 fabrics and T50018 mesh combination describedabove, satisfactory laminate structures 66 and/or 67 having firststrands 24 integrally bonded to first and second carrier layers 37 and38 can be provided if first plate 158 is heated to a temperature T₁ offrom about 110° C. to about 130° C. and a bonding pressure P_(f) ofbetween 350 to 700 grams force per cm² is applied between first plate158 and second plate 160 for from about 10 to about 20 seconds.

While the above description describes the process for making firstthermal bonded elastic laminate 66 (i.e., comprising first carrier layer37, first elastic member 36, and second carrier layer 38), an identicalprocess for making second thermal bonded elastic laminate 67 (i.e.,comprising third carrier layer 40, second elastic member 39, and fourthcarrier layer 41) may be utilized.

It is believed that properly selecting the strand density, strandcross-sectional area, and/or the melt index of first strands 24 (iffirst strands 24 are formed of a polymer) is necessary in order toprovide laminate structures 66 and/or 67 having an elastic structuraldirection along the direction of the second strands 27. Improperselection of strand density, strand cross-sectional area, and/or meltindex of first strands 24 can result in a laminate structure whereinportions of integrally bonded first strands 25 can overlap or mergetogether in laminate structures 66 and/or 67. Such merging or overlap ofintegrally bonded first strands 25 can result in only small portions oflaminate second strands 27 being able to extend or elongate whensubjected to a tensile force, as opposed to the elongation beingdistributed along substantially the entire length of substantially allof laminate second strands 27 absent this overlap. To minimize thiscondition, the strand density, strand cross-sectional area, and/or meltindex of first strands 24 should be selected such that integrally bondedfirst strands 25 have a strand coverage S_(c) of less than about 50%. Asused herein, the phrase "strand coverage" is intended to be a measure ofthe amount of surface area of first carrier layer inner surface 50 andsecond carrier layer inner surface 52 which is in contact withintegrally bonded first strands 25 of the present invention. Strandcoverage SC is defined as:

    S.sub.c =(E-F)/E*100

Where

E=strand centerline distance between any adjacent integrally bondedfirst strands 25, as shown in FIG. 4

F=strand edge distance F between any adjacent integrally bonded firststrands 25, as shown in FIG. 4

The measurements of E and F can be taken at any cross section throughlaminate structure 66 and/or 67 between any adjacent integrally bondedfirst strands

The phrase "strand density", as used herein, is intended to mean thenumber of subject strands per centimeter along a strand transverse tothe subject strands. For example, first strands 24 have a strand densitywhich can be measured over a predetermined length A of a second strand26, as shown in FIG. 3. Likewise, second strands 26 have a stranddensity which can be measured over a predetermined length B of a firststrand 24. The phrase "strand cross-sectional area", as used herein, isintended to mean the cross-sectional area of any first strand 24 whenmeasured according to techniques known in the art.

The melt index of a polymer measures the ability of the polymer to flowwhen subjected to a given temperature or pressure. A polymer having alow melt index will be more viscous (and therefore not flow as readily)at a given temperature than a polymer having a higher melt index. Thus,it is believed that first strands 24 comprising a polymer having a highmelt index will have a greater tendency to merge or overlap duringapplication of a given pressure and heat flux than first strands 24comprising a polymer having a lower melt index and subjected to the samepressure and heat flux. Because of this variability, the polymer formingfirst strands 24 can be selectively chosen, in conjunction with thestrand density and strand cross-sectional area, to provide apredetermined melt index such that first strands 24 are integrallybonded to first and second carrier layer 37 and 38 with a strandcoverage S_(c) of about 50 percent. In addition, varying the polymermelt index can also be especially useful where it is desired to increasethe density of first and second carrier layers 37 and 38 whilemaintaining the same processing conditions. In this situation, thepolymer of first strands 24 can be changed to provide a higher meltindex such that first strands 24 can more easily penetrate and bond withcarrier layer 37, 38, 40, and/or 41 when subjected to the predeterminedpressure and heat flux. Consequently, the same level of integral bondingcan be achieved without changing the processing conditions despite theincreased density of carrier layers 37, 38, 40, and/or 41.

Based upon the foregoing, it is believed that first strands 24 shouldpreferably be aligned so as to provide a strand density of from about 2to about 10 strands per centimeter in conjunction with a strandcross-sectional area of from about 0.0005 cm² to about 0.03 cm², morepreferably from about 3 to about 6 strands per centimeter in conjunctionwith a strand cross-sectional area of from about 0.001 cm² to about0.005 cm², so that merger or overlap of integrally bonded first strands25 in laminate structure 66 and/or 67 can be avoided. A melt index offrom about 2 to about 15 (as measured per ASTM D1238) in conjunctionwith the above-described strand density and strand cross-sectional areavalues has been found to be satisfactory. With regard to second strands26, it is believed that the strand density, strand cross-sectional area,and modulus of second strands 26 can also affect the elastic propertiesof laminate structures 66 and/or 67 (i. e., the modulus of laminatestructures 66 and/or 67) in the direction along the second strands 26(i. e., along irection D of FIG. 4). For example, as the strand densityand/or the strand cross-sectional area of second strands 26 increases,the modulus of laminate structures 66 and/or 67 will decrease. Forlaminate structures 66 and/or 67 to be incorporated into the wraps ofthe present invention, it is desirable that a modulus of from about 100to about 250 grams force per cm, at a strain ε.sub.μ of about 1 beprovided. It is believed that providing second strands 26 having astrand density of from about 2 to about 5, a cross-sectional area offrom about 0.003 cm² to about 0.02 cm², and comprising a styrenebutadiene block copolymer will provide laminate structures 66 and/or 67having the preferred modulus in a direction along second strands 26. Themodulus of laminate structures 66 and/or 67 can be measured bytechniques known in the art. For example, the modulus of laminatestructures 66 and/or 67 can be measured using a universal constant rateof elongation tensile tester, such as Instron Model #1122, manufacturedby Instron Engineering Corp., Canton, Mass.

Laminate structures 66 and/or 67 can also be subjected to variousadditional post-formation processes known in the art. For example, alaminate structure made in accordance herewith can comprise additionalfabric layers (i.e., bulking layers) which are joined to the laminatestructure so as to further improve the wearability and comfort of thestructure. The additional fabric layers can be secured to the laminatestructure by adhesive, thermal bonding, pressure bonding, ultrasonicbonding, dynamic mechanical bonding, or any other suitable methods knownin the art.

To improve the elastic performance of wrap 10, elastic portion 20 may besubjected to an activation process after assembly and prior to use. Thisactivation process stretches and permanently deforms on a very smallscale the nonelastic layers of wrap 10. This activation process allowsfirst and/or second thermal bonded elastic laminate 66 and/or 67 tostretch or expand in the direction of an applied force and essentiallyreturn to their original dimensions upon removal of the force,unencumbered by the nonelastic layers of elastic portion 20.

Alternatively, elastic portion 20 may be assembled while first and/orsecond thermal bonded elastic laminates 66 and/or 67 are held in anextended state. After assembly, the first and/or second thermal bondedelastic laminates 66 and/or 67 are allowed to return to their relaxedstate causing the nonelastic layers of elastic portion 20 to fold andbuckle creating rugosities. Subsequent stretching of elastic portion 20will result in the unfolding of these rugosities.

In a preferred embodiment of the present invention there is a secondelastic portion 56 located intermediate heat cells 75 and/or thermalpacks 22. Materials and processes used to deliver elastic portion 20described herein above may also be used to deliver second elasticportion 56.

A particular embodiment of wrap 10 is described which has two thermalbonded elastic laminates 66 and 67, which are coextensive body-facingmaterial 62 and outer surface material 64. Preferably, first and secondthermal bonded elastic laminates 66 and 67 extend from first end 14 tosecond end 16 of flexible material 12. Alternatively, first and secondthermal bonded elastic laminates 66 and 67 may extend from first end 14to interfacial centerline 54 of flexible material 12 to provide elasticproperties to first and second straps 80 and 82. Interfacial centerline54 is preferably aligned perpendicular to longitudinal axis 18 locatedbetween first end 14 and second end 16.

A particular embodiment of wrap 10 is described which utilizes a numberof layers. Alternatively, wrap 10 could be comprised of a single elasticmember. First carrier layer 37 and second carrier layer 38 are employedduring the thermal bonding of first elastic member 36 and third carrierlayer 40 and fourth carrier layer 41 are employed during the thermalbonding of second elastic member 39. If the thermal bonding step is notused for any number of reasons, then first carrier layer 37, secondcarrier layer 38, third layer 40, and fourth carrier layer 41, may beomitted.

Body-facing material 62 of flexible material 12 comprises body-facingsurface 28 coextensive from first end 14 to second end 16. Body-facingmaterial 62 comprises a plurality of loop elements 102 which are formedfrom fibers of material 62. Similarly, outer surface material 64 offlexible material 12 comprises outer surface 30 coextensive from firstend 14 to second end 16. Outer facing material 64 comprises a pluralityof loop elements 104 which are formed from fibers of material 64. Theplurality of loop elements 102 and 104 serve as one-half of a reclosablehook and loop fastening system. As used herein, the term "reclosable",refers to that property of a fastening system which provides for initialclosing of the fastening system, a subsequent opening of the fasteningsystem, followed by at least one additional closings of the samefastening system. The subsequent closing of the fastening system mayeither return the closure to the original position or it may result in arepositioning of the closure from the initial configuration.

Body-facing surface 28 comprises at least one hook member 34 which ispermanently attached to body-facing surface 28 near first end 14.Similarly, outer surface 30 comprises at least one hook member 32 whichis permanently attached to outer surface 30 near second end 16. Theplurality of hooks on hook members 32 and 34 serves as the second halfof a reclosable hook and loop fastening system. As used herein, the term"permanently attached", is defined as the joining of two or moreelements which remain joined during their intended use.

Hook member 32 with loop elements 102 and hook member 34 with loopelements 104, provide a reclosable hook and loop fastening system forsecuring wrap 10 around the user's knee or elbow.

Alternatively, the reclosable fastening system of wrap 10 may be asingle hook and loop fastening system comprising either hook member 32and loop elements 102 or hook member 34 and loop elements 104.

Body-facing material 62 and outer surface material 64 may be any numberof different materials which include, but are not limited to, woven andknit fabrics, carded nonwovens, spunbond nonwovens, and the like. Amaterial that has been found to be particularly suitable for body-facingmaterial 62 and outer surface material 64 is a carded thermally bondednonwoven of polypropylene with a basis weight of 32 grams per squaremeter (gsm). This material is available as grade #9327786, from Veratec,Walpole, Mass.

The hooks of hook members 32 and 34 may be any number of styles, shapes,and/or densities depending upon the use. The hooks of hook members 32and 34 may be bent shafts, mushroom capped, harpoon-shaped, or any othersuitable shape, unidirectional, bi-directional, or omni-directional,depending upon the application and companion loop elements of loopmembers 102 and 104. The hooks of hook members 32 and 34 must be chosenin conjunction with companion loop elements of loop members 102 and 104so as to provide the peel and shear forces that are required fordifferent applications.

The attachment of layers to form body-facing laminate 92, outer surfacelaminate 93 and, finally, wrap 10 may be achieved by any number ofattachment means known in the art. These include, but are not limitedto, hot melt adhesive including spiral sprays, meltblown, control coat,and the like, latex adhesives applied via spray, printing gravure, andthe like, thermal bonding, ultrasonic, pressure bonding, and the like.One particular method that has been used successfully is hot meltadhesive layer 60 available as 70-4589 from National Starch and ChemicalCo., Bridgewater, N.J., applied via a spiral hot melt system at a rateof from about 0.5 to about 25 mg/cm².

Flexible material 12 preferably comprises first strap portion 80 andsecond strap portion 82, each having at least one hook member 34 whichcan be independently fastened to loop members 104. Upon application ofwrap 10, first end 14 of upper strap portion 80 encircles behind theuser's knee or in front of the user's elbow, preferably above the kneeor elbow, and first end 14 of second strap portion 82 encircles behindthe user's knee or in front of the user's elbow, preferably below theknee or elbow. First end 14 of first and second strap portions 80 and 82overlap second end 16 such that, hook members 32 on outer surface 30near second end 16 engage loop elements 102 on body-facing surface 28.Engagement of hook members 32 with loop elements 102 forms the firstpart of the two-part hook and loop fastening system. Continuing theapplication, hook members 34 on the body-facing surface 28 near firstend 14 are placed in contact with loop elements 104 of outer surface 30forming the second part of a two-part hook and loop fastening system.First strap portion 80 and second-strap portion 82 allow easierapplication and differential tensioning of material 12 during use.Additional strap portions may optionally be included.

Preferably, first and second strap portions 80 and 82 contain elasticportion 20 of flexible material 12. That is first and second strapportions 80 and 82 preferably exhibit elastic behavior when stretched ina direction parallel to longitudinal axis 18.

Flexible material 12 preferably comprises a body portion 81. Bodyportion 81 has a first edge 83 and a second edge 84. The distancebetween first edge 83 and second edge 84 measured in a directiontransverse longitudinal axis 18 is the width of body portion 81 offlexible material 12. First strap portion 80 of flexible material 12 hasa first edge 85 and a second edge 86. The distance between first edge 85and second edge 86 measured in a direction transverse longitudinal axis18 is the width of first strap portion 80 of flexible material 12.Second strap portion 82 of flexible material 12 has a first edge 87 anda second edge 88. The distance between first edge 87 and second edge 88measured in a direction transverse longitudinal axis 18 is the width ofsecond strap portion 82 of flexible material 12.

Flexible material 12 preferably comprises an aperture 46 betweeninterfacial centerline 54 and second end 16. Aperture 46 is intended tobe aligned with the wearer's patella or olecranon and serves to helpproperly position wrap 10 during use. Preferably, flexible material 12has at least one slit 48, more preferably two slits, extending fromaperture 46, one toward second end 16 and the other toward interfacialcenterline 54. Slit(s) 48 allows flexible material 12 to expand andclose respectively as the user bends and straightens his/her knee orelbow. Slit(s) 48 may be of any shape, however, the rectangular shape,as depicted in FIG. 1, is preferred. In the alternative, flexiblematerial 12 may comprise slit 48 without aperture 46.

Wrap 10 may further comprise stays 100. Stays 100 are preferablyembedded transverse to the longitudinal axis 18 and internally in thelayers of flexible material 12 of wrap 10 and positioned adjacentinterfacial centerline 54 and/or second end 16 of flexible material 12.Stays 100 are preferably stripes of glue which are positioned to permitwrap 10 to bend with the knee or elbow, but minimizes bunching offlexible material 12, which would otherwise occur after several knee orelbow bending cycles. Stays 100 serve as resilient stiffeners to causewrap 10 to maintain its flatness against the user's leg or arm.Alternatively, stays 100 may be positioned on the outer surface 30 ofwrap 10. Typically, stays 100 extend to just short of the perimeteredges of wrap 10 so that the stiff ends of stays 100 are never incontact with user's leg or arm. However in a second alternative, thestays 100 may be positioned on body-facing surface 28 to increasefriction between wrap 10 and user's leg or arm in order to reduceslippage of wrap 10 during use.

A preferred glue for stays 100 is HL1460-X made by Fuller, Minneapolis,Minn. Beads of about 5 mm in diameter are extruded onto the flexiblematerial 12 with a conventional hot melt glue gun. The glue beads arethen calendered or flattened via a compression roll to a thickness offrom about 0.3 mm to about 5 mm, which determines the desired stays 100stiffness.

Alternatively, stays 100 may be made of rigid plastic or metal becausethese materials may be applied more easily and are less costly toinclude. With rigid plastic and metal stays, pockets are typically sewninto wrap 10, and then individual stays are formed and installed.

Body-facing surface 28 may optionally comprise foamed polymer stripsaligned transverse to longitudinal axis 18 of flexible material 12 forincreasing friction between wrap 10 and wearer's knee or elbow. Ifpresent, foamed polymer strips are typically located adjacent second end16 and interfacial line 54. The increased friction provided by foamedpolymer strips serves to reduce slippage or relative movement betweenwrap 10 and the wearer. If present, the foam strips are typically about25 mm wide and about 1.5 mm thick. High-tack polymers such as ethylenevinyl acetate copolymer (EVA) may be used instead of foamed polymerstrips. The polymer strips may also serve as stays 100 and may be glued,thermally bonded or printed onto body-facing surface 28.

Wrap 10 also comprises one or more heat cells 75, preferably arranged ina pattern, as indicated in FIG. 1. Heat cells 75 apply heat energy tothe sides and top of the knee or elbow when flexible material 12 issecured around the user's knee or elbow. Heat cells 75 are typicallyconstructed by forming a pocket 76 in base material 70. Pocket 76 inbase material 70 is then filled with an exothermic composition 74. Afterfilling pocket 76 in base material 70 with an exothermic composition 74,a cover material 72 is placed over pocket 76 and heat sealed to basematerial 70 around the periphery of pocket 76, encapsulating exothermiccomposition 74, thereby forming heat cell 75.

Heat cells 75 are spaced apart from each other and each heat cell 75functions independently of the rest of the heat cells 75. Each heat cell75 preferably comprise a densely packed, particulate exothermiccomposition 74 which preferably substantially fills the available cellvolume within the cell reducing any excess void volume therebyminimizing the ability of exothermic composition 74 to shift within thecell. Alternatively, exothermic composition 74 may be compressed intodirect compaction articles before being placed into each cell.

Because the heat generating material is densely packed or compressedinto direct compaction articles, heat cells 75 is not readily flexible.Therefore, the spacing apart of heat cells 75 and the materials selectedfor base material 70 and cover material 72 between heat cells 75 allowswrap 10 to easily conform to the user's knee or elbow. Preferably, wrap10 comprises one or more thermal packs 22 which comprise a plurality ofindividual heat cells 75, preferably embedded within the laminatestructure of the thermal pack 22.

Thermal pack 22 may be made of any number of thermoplastic materials;however, it is preferred that base material 70 and/or cover material 72be made of thermoplastic materials which are semirigid at a temperatureof about 25° C. and below and which soften, i. e., become substantiallyless rigid, at a temperature above about 25° C. Different materials maybe capable of satisfying the specified requirement provided that thethickness is adjusted accordingly. Such materials include, but are notlimited to, polyethylene, polypropylene, nylon, polyester, polyvinylchloride, polyvinylidene chloride, polyurethane, polystyrene, saponifiedethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer,natural rubber, reclaimed rubber, synthetic rubber, and mixturesthereof. These materials may be used alone or coextruded with a low melttemperature polymer including, but not limited to, ethylene vinylacetate copolymer, low density polyethylene, and mixtures thereof. Suchmaterials are also capable of containing exothermic composition 74 andlimiting oxygen flow into pocket 76 and provides sufficient rigidity toprevent wrap 10 from folding or bunching during use, preventingunacceptable stretching of structures of the continuous layer duringprocessing or use, and deterring easy access to the heat cell contents.

A particular base material 70 and cover material 72, which has proven tobe satisfactory, preferably comprises a coextruded film, having a firstside of polypropylene and a second side of EVA, and having a combinedthickness of from about 20 μm to about 30 μm, preferably about 25 μm.The polypropylene comprises from about 10% to about 90%, preferably fromabout 40% to about 60%, of the thickness of base material 70 and covermaterial 72. When coextruded films of the type just described are usedfor base material 70 and cover material 72, the EVA sides are preferablyoriented toward each other to facilitate thermal bonding of covermaterial 72 to base material 70.

Exothermic composition 74 may comprise any composition capable ofproviding heat. However, exothermic composition 74 preferably comprisesa particulate mix of chemical compounds that undergo an oxidationreaction during use. Exothermic composition 74 may also be formed intoagglomerated granules, direct compacted into compaction articles such asgranules, pellets, tablets, and/or slugs, and mixtures thereof. The mixof compounds typically comprises iron powder, carbon, a metal salt(s),and water. Mixtures of this type react when exposed to oxygen, providingheat for several hours. Exothermic compositions suitable for inclusionin wrap 10 of the present invention may be found in WO9701313, publishedJan. 16, 1997, to Burkett, et al., incorporated in its entirety hereinby reference.

Heat cells 75 may comprise any geometric shape, e.g., disk, triangle,pyramid, cone, sphere, square, cube, rectangle, rectangularparallelepiped, cylinder, ellipsoid and the like. The preferred shape ofheat cell 75 comprises a disk shaped geometry having a cell diameter offrom about 0.2 cm to about 10 cm, preferably from about 0.5 cm to about8 cm, more preferably from about 1 cm to about 5 cm, and most preferablyfrom about 1.5 cm to about 3 cm. Heat cell 75 may comprise a height offrom about 0.08 cm to about 1 cm, preferably from about 0.15 cm to about0.9 cm, more preferably greater than from about 0.2 cm to about 0.8 cm,and most preferably about 0.4 cm.

The ratio of fill volume to cell volume of heat cell 75 is from about0.7 to about 1.0, preferably from about 0.75 to about 1.0, morepreferably from about 0.8 to about 1.0, even more preferably from about0.85 to about 1.0, and most preferably from about 0.9 to about 1.0.

Oxygen permeability can be provided by selecting materials for the basematerial 70 and/or cover material 72 that have the specifically desiredpermeability properties. The desired permeability properties may beprovided by microporous films or by films which have pores or holesformed therein. The formation of these holes/pores may be via extrusioncast/vacuum formation or by hot needle aperturing. Oxygen permeabilitycan also be provided by perforating at least one of the base material 70and cover material 72 with aeration holes using, for example, an arrayof pins having tapered points and diameters of from about 0.2 mm toabout 2 mm, preferably from about 0.4 mm to about 0.9 mm. Oxygendiffusion into heat cell 75 during oxidation of the exothermiccomposition 74 typically ranges from about 0.01 cc O₂ /min./5 cm² toabout 15.0 cc O₂ /min./5 cm² (at 21° C., 1 ATM), preferably from about0.9 cc O₂ /min./5 cm² to about 3 cc O₂ /min./5 cm² (at 21° C., 1 ATM).

The velocity, duration, and temperature of the thermogenic oxidationreaction of the exothermic composition 74 can be controlled as desiredby changing the area of contact with air, more specifically, by changingthe oxygen diffusion/permeability.

Elastic thermal uniaxial joint wrap 10 may optionally comprise a layerof material located preferably on body-facing surface 28 of flexiblematerial 12. The layer of material is generally coextensive flexiblematerial 12 from second end 16 to interfacial centerline 54. The layerof material has elasticity in a direction transverse to longitudinalaxis 18 of flexible material 12 and preferably, has an elastic recoveryforce which is as low as possible to minimize forces transverse tolongitudinal axis 18. The layer of material is typically attached tobody-facing surface 28 along the perimeter of the layer of materialusing an adhesive. The layer of material provides coverage of the kneeor elbow when the user's knee or elbow is bent and flexible material 12expands separating slit(s) 48. Such a material may comprise a flexiblethermal laminate, such as those described herein for first and secondthermal layer elastic laminates 66 and 67.

Alternatively the layer of material may have elasticity in a directionparallel to longitudinal axis 18 in addition to elasticity in adirection transverse to longitudinal axis 18.

When assembling wrap 10 for a knee, the width of body portion 81 offlexible material 12 is preferably from about 15 cm to about 25 cm, morepreferably from about 18 cm to about 23 cm and most preferably fromabout 19 cm to about 21 cm. The width of first strap portion 80 andsecond strap portion 82 of flexible material 12 is typically less thanthe width of body portion 81 of flexible material 12, preferably fromabout 2.5 cm to about 13 cm, more preferably from about 4 cm to about 8cm, and most preferably from about 5 cm to about 7 cm.

When assembling wrap 10 for an elbow, the above described dimensions arepreferably scaled appropriately to fit a user's elbow.

Preferably, finished wrap 10 is typically enclosed within asubstantially oxygen impermeable package. To use, wrap 10 is removedfrom the oxygen impermeable package allowing oxygen to enter heat cell75 and react with exothermic composition 74.

While particular embodiments of the present invention have beenillustrated and described, it will be obvious to those skilled in theart that various changes and modifications may be made without departingfrom the spirit and scope of the invention, and it is intended to coverin the appended claims all such modifications that are within the scopeof the invention.

What is claimed is:
 1. A disposable elastic thermal uniaxial joint wrapcomprising:a) a piece of flexible material having a first end and asecond end, a body portion fixed between said first end and said secondend, a first strap portion, and a second strap portion, wherein at leastone of said body portion, first strap portion, and second strap portion,comprises one or more elastic laminate structures, said laminatestructures comprising a first carrier layer, a second carrier layer, anda mesh disposed between said carrier layers, said mesh having aplurality of first strands intersecting a plurality of elastic secondstrands, said first and second strands having softening temperatures atan applied pressure, at least about 10% of said first strands beingintegrally bonded to said first carrier layer and said second carrierlayer by application of a bonding pressure at said softening temperatureof said first strands, wherein at least one of said body portion, firststrap portion, and second strap portion is stretchable along alongitudinal axis of said piece of flexible material; b) one or moreheat cells comprising an exothermic composition spaced apart and fixedlyattached across said body portion; and c) a fastening means to hold saidpiece of flexible material around a user's knee or elbow.
 2. Adisposable elastic thermal uniaxial joint wrap according to claim 1wherein at least 50% of said first strands are integrally bonded to saidfirst carrier layer and said second carrier layer.
 3. A disposableelastic thermal uniaxial joint wrap according to claim 2 wherein atleast 90% of said first strands are integrally bonded to said firstcarrier layer and said second carrier layer.
 4. A disposable elasticthermal uniaxial joint wrap according to claim 1 wherein said softeningtemperatures of said first and second strands are distinct at saidbonding pressure, the softening temperature of said first strands beingless than the softening temperature of said second strands.
 5. Adisposable elastic thermal uniaxial joint wrap according to claim 1wherein said first carrier layer and said second carrier layer each havean outer surface and at least about 50% of said integrally bonded firststrands are substantially flat in shape and coplanar with said outersurfaces.
 6. A disposable elastic thermal uniaxial joint wrap accordingto claim 1 wherein at least 25% of said second strands have asubstantially elliptical cross-sectional shape.
 7. A disposable elasticthermal uniaxial joint wrap according to claim 6 wherein at least 50% ofsaid second strands have a substantially elliptical cross-sectionalshape.
 8. A disposable elastic thermal uniaxial joint wrap according toclaim 7 wherein at least 90% of said second strands have a substantiallyelliptical cross-sectional shape.
 9. A disposable elastic thermaluniaxial joint wrap according to claim 1 wherein said integrally bondedfirst strands have a strand coverage of less than about 50 percent. 10.A disposable elastic thermal uniaxial joint wrap according to claim 1wherein said heat cells comprise a densely packed particulatecomposition comprising iron powder, carbon, a metal salt, and water,said composition substantially fills the available cell volume withinsaid heat cell reducing any excess void volume thereby minimizing theability of said particulate composition to shift within said heat cells.11. A disposable elastic thermal uniaxial joint wrap according to claim10 wherein said heat cells comprise the shape of a disk having adiameter of from about 0.2 cm to about 10 cm and a height of greaterthan from about 0.2 cm to about 1.0 cm.
 12. A disposable elastic thermaluniaxial joint wrap according to claim 11 wherein said heat cellscomprise an exothermic composition having a physical form selected fromthe group consisting of dry agglomerated granules, direct compactionarticles, and mixtures thereof, said compaction articles are selectedfrom the group consisting of granules, pellets, tablets, slugs, andmixtures thereof.
 13. A disposable elastic thermal uniaxial joint wrapaccording to claim 1 wherein said strap portions comprise said elasticlaminate structures.
 14. A disposable elastic thermal uniaxial jointwrap according to claim 1 wherein said body portion further comprises anaperture intended to be aligned with the user's patella or olecranon toestablish a convenient locating point for wrapping said wrap around theuser's knee or elbow.
 15. A disposable elastic thermal uniaxial jointwrap according to claim 14 wherein said body portion further comprisesat least one slit extending substantially longitudinally from saidaperture for enabling said piece of flexible material to stretchtransverse to said longitudinal axis at said aperture in order toaccommodate bending of the user's knee or elbow.
 16. A disposableelastic thermal uniaxial joint wrap according to claim 1 wherein saidbody portion further comprises at least one slit extending substantiallyalong the longitudinal axis of said body portion enabling said piece offlexible material to stretch transverse to said longitudinal axis ofsaid body portion in order to accommodate bending of the user's knee orelbow.
 17. A disposable elastic thermal uniaxial joint wrap according toclaim 1 wherein said flexible material further comprises one or morestays to resiliently stiffen said flexible material and thereby minimizebunching of said flexible material when said user's knee or elbow isrepeatedly bent.
 18. A disposable elastic thermal uniaxial joint wrapaccording to claim 1 wherein said fastening system is reclosable.
 19. Adisposable elastic thermal knee wrap according to claim 18 wherein saidreclosable fastening system comprises a hook and loop fastening system.20. A disposable elastic thermal uniaxial joint wrap according to claim19 wherein said reclosable fastening system comprises a two part hookand loop fastening system.
 21. A disposable elastic thermal uniaxialjoint wrap comprising:a) a piece of flexible material having a first endand a second end, a body portion fixed between said first end and saidsecond end, a first strap portion, and a second strap portion, whereinat least one of said body portion, first strap portion, and second strapportion, comprises one or more elastic laminate structures, saidlaminate structures comprising a first carrier layer, a second carrierlayer, and a mesh disposed between said carrier layers, said mesh havinga plurality of first strands intersecting a plurality of elastic secondstrands, said first and second strands having softening temperatures atan applied pressure, at least about 10% of said first strands beingintegrally bonded to said first carrier layer and said second carrierlayer by application of a bonding pressure at said softening temperatureof said first strands, wherein at least one of said body portion, firststrap portion, and second strap portion is stretchable along alongitudinal axis of said piece of flexible material; b) one or morethermal packs fixedly attached to said body portion, each thermal packhaving a unified structure comprising at least one continuous layer ofmaterial and a plurality of individual heat cells spaced apart andfixedly attached to said continuous layer of material; and c) afastening means to hold said piece of flexible material around a user'sknee or elbow.
 22. A disposable elastic thermal uniaxial joint wrapaccording to claim 21 wherein said softening temperatures of said firstand second strands are distinct at said bonding pressure, the softeningtemperature of said first strands being less than the softeningtemperature of said second strands.
 23. A disposable elastic thermaluniaxial joint wrap according to claim 21 wherein said first carrierlayer and said second carrier layer each have an outer surface and atleast about 50% of said integrally bonded first strands aresubstantially flat in shape and coplanar with said outer surfaces.
 24. Adisposable elastic thermal uniaxial joint wrap according to claim 21wherein at least 25% of said second strands have a substantiallyelliptical cross-sectional shape.
 25. A disposable elastic thermaluniaxial joint wrap according to claim 21 wherein said integrally bondedfirst strands have a strand coverage of less than about 50 percent. 26.A disposable elastic thermal uniaxial joint wrap according to claim 21wherein said thermal pack comprises at least one continuous layer of acoextruded material having a first side of polypropylene and a secondside of a low melt temperature copolymer, wherein said continuous layeris semirigid at a temperature of about 25° C. and below, andsubstantially less rigid at a temperature of above about 25° C.
 27. Adisposable elastic thermal uniaxial joint wrap according to claim 21wherein said heat cells comprise a densely packed particulatecomposition comprising iron powder, carbon, a metal salt, and water,said composition substantially fills the available cell volume withinsaid heat cell reducing any excess void volume thereby minimizing theability of said particulate composition to shift within said heat cells.28. A disposable elastic thermal uniaxial joint wrap according to claim21 wherein said heat cells comprise an exothermic composition having aphysical form selected from the group consisting of dry agglomeratedgranules, direct compaction articles, and mixtures thereof, saidcompaction articles are selected from the group consisting of granules,pellets, tablets, slugs, and mixtures thereof.
 29. A disposable elasticthermal uniaxial joint wrap according to claim 21 wherein said strapportions comprise said elastic laminate structures.
 30. A disposableelastic thermal uniaxial joint wrap according to claim 21 wherein saidbody portion further comprises an aperture intended to be aligned withthe user's patella or olecranon to establish a convenient locating pointfor wrapping said wrap around the user's knee or elbow.
 31. A disposableelastic thermal uniaxial joint wrap according to claim 30 wherein saidbody portion further comprises at least one slit extending substantiallylongitudinally from said aperture for enabling said piece of flexiblematerial to stretch transverse to said longitudinal axis at saidaperture in order to accommodate bending of the user's knee or elbow.32. A disposable elastic thermal uniaxial joint wrap according to claim21 wherein said body portion further comprises at least one slitextending substantially along the longitudinal axis of said body portionenabling said piece of flexible material to stretch transverse to saidlongitudinal axis of said body portion in order to accommodate bendingof the user's knee or elbow.
 33. A disposable elastic thermal uniaxialjoint wrap according to claim 21 wherein said flexible material furthercomprises one or more stays to resiliently stiffen said flexiblematerial and thereby minimize bunching of said flexible material whensaid user's knee or elbow is repeatedly bent.
 34. A disposable elasticthermal uniaxial joint wrap according to claim 21 wherein said fasteningsystem is reclosable.
 35. A disposable elastic thermal knee wrapaccording to claim 34 wherein said reclosable fastening system comprisesa hook and loop fastening system.
 36. A disposable elastic thermaluniaxial joint wrap according to claim 35 wherein said reclosablefastening system comprises a two part hook and loop fastening system.